Objective-C

Google Photos OAuth2 Access Token

See more Google Photos Examples

Demonstrates how to get a Google Photos OAuth2 access token from a desktop application or script. Objective-C

#import <CkoOAuth2.h>
#import <NSString.h>
#import <CkoStringBuilder.h>

BOOL success = NO;

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

CkoOAuth2 *oauth2 = [[CkoOAuth2 alloc] init];

// For Google OAuth2, set the listen port equal to the port used
// in the Authorized Redirect URL for the Client ID.
// For example, in this case the Authorized Redirect URL would be http://localhost:3017/
// Your app should choose a port not likely not used by any other application.
oauth2.ListenPort = [NSNumber numberWithInt:3017];

oauth2.AuthorizationEndpoint = @"https://accounts.google.com/o/oauth2/v2/auth";
oauth2.TokenEndpoint = @"https://www.googleapis.com/oauth2/v4/token";

// Replace these with actual values.
oauth2.ClientId = @"GOOGLE-CLIENT-ID";
oauth2.ClientSecret = @"GOOGLE-CLIENT-SECRET";

oauth2.CodeChallenge = YES;
oauth2.CodeChallengeMethod = @"S256";

// This is a scope for Google Photos.  See https://developers.google.com/photos/library/guides/authentication-authorization
// This scope provides read/write access but not sharing.
oauth2.Scope = @"https://www.googleapis.com/auth/photoslibrary";

// Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
NSString *url = [oauth2 StartAuth];
if (oauth2.LastMethodSuccess == NO) {
    NSLog(@"%@",oauth2.LastErrorText);
    return;
}

// Launch the system's default browser navigated to the URL.
success = [oauth2 LaunchBrowser: url];
if (success == NO) {
    NSLog(@"%@",oauth2.LastErrorText);
    return;
}

// Now wait for the authorization.
// We'll wait for a max of 120 seconds.
int numMsWaited = 0;
while ((numMsWaited < 120000) && ([oauth2.AuthFlowState intValue] < 3)) {
    [oauth2 SleepMs: [NSNumber numberWithInt: 100]];
    numMsWaited = numMsWaited + 100;
}

// If there was no response from the browser within 120 seconds, then 
// the AuthFlowState will be equal to 1 or 2.
// 1: Waiting for Redirect. The OAuth2 background thread is waiting to receive the redirect HTTP request from the browser.
// 2: Waiting for Final Response. The OAuth2 background thread is waiting for the final access token response.
// In that case, cancel the background task started in the call to StartAuth.
if ([oauth2.AuthFlowState intValue] < 3) {
    [oauth2 Cancel];
    NSLog(@"%@",@"No response from the browser!");
    return;
}

// Check the AuthFlowState to see if authorization was granted, denied, or if some error occurred
// The possible AuthFlowState values are:
// 3: Completed with Success. The OAuth2 flow has completed, the background thread exited, and the successful JSON response is available in AccessTokenResponse property.
// 4: Completed with Access Denied. The OAuth2 flow has completed, the background thread exited, and the error JSON is available in AccessTokenResponse property.
// 5: Failed Prior to Completion. The OAuth2 flow failed to complete, the background thread exited, and the error information is available in the FailureInfo property.
if ([oauth2.AuthFlowState intValue] == 5) {
    NSLog(@"%@",@"OAuth2 failed to complete.");
    NSLog(@"%@",oauth2.FailureInfo);
    return;
}

if ([oauth2.AuthFlowState intValue] == 4) {
    NSLog(@"%@",@"OAuth2 authorization was denied.");
    NSLog(@"%@",oauth2.AccessTokenResponse);
    return;
}

if ([oauth2.AuthFlowState intValue] != 3) {
    NSLog(@"%@%d",@"Unexpected AuthFlowState:",[oauth2.AuthFlowState intValue]);
    return;
}

// Save the full JSON access token response to a file.
CkoStringBuilder *sbJson = [[CkoStringBuilder alloc] init];
[sbJson Append: oauth2.AccessTokenResponse];
[sbJson WriteFile: @"qa_data/tokens/googlePhotos.json" charset: @"utf-8" emitBom: NO];

// The saved JSON response looks like this:
// {
//   "access_token": "ya29.GlamBqWR6cp8lEfJMmTHVEua45912XLKoq4djyHl_Z3CEIzsPLIZkJSGie5oOrbaggy1rjJHn1zW5bjqSesGr5MEYIp9Hx-0CuvjVYf8srg2jeaDMwMACvzemp43",
//   "expires_in": 3600,
//   "refresh_token": "1/rl6k16nysDl9Bp1EhRH9F1WyRIoiSQAvko49Z4yY694MT5V1QXLj2ibNZGaRgek0",
//   "scope": "https://www.googleapis.com/auth/photoslibrary",
//   "token_type": "Bearer"
// }

NSLog(@"%@",@"OAuth2 authorization granted!");
NSLog(@"%@%@",@"Access Token = ",oauth2.AccessToken);